The present invention relates to an in-situ lapping apparatus for grinding valve body seats of a gate valve.
Ships and submarines are large users of gate valves within their various piping systems. These piping systems are periodically inspected for leaks which are caused by normal operational fatigue. Most leaks are caused by improper seating of the wedge-shaped gate with the pair of valve body seats. Excessive wear of these valve body seats are refurbished in the same manner as valve seats of the ordinary combustion engine. The valve seats are ground smooth again so that proper sealing takes place. This is especially important in critical fluid systems aboard ships or submarines.
Normally, valve body seats are resurfaced in place within the piping system, using the gate as the lapping tool with the aid of a grinding compound and/or by the use of a tool which is similar to the gate valve. This approach has not been satisfactory in three primary instances: (1 where cleanliness is to be maintained within the piping system, (2 where the sealing surfaces are extremely defaced, and/or (3 where the allowable geometric tolerances of the sealing surfaces are close.